Effects of Amendment Materials on Cement-Solidified Contaminated Marine Sediments-Mechanical Stability and Leaching of Heavy Metals

摘要

Stabilization/solidification technology (S/S), in which contaminated marine sediments are mixed with cement and other binding agents have shown to be a promising remediation technique. The major advantage of S/S over other contaminated sediments remediation techniques is that dredged material can be transformed from a soft material into a filling material with favorable geotechnical properties. Reduced contaminant transport from the treated material is achieved simultaneously. This paper summarizes a study investigating how amendments (additions) may improve the mechanical properties and reduce leaching of heavy metals of two cement-stabilized marine harbor sediments from the cities of Bergen and Hammer-fest, Norway. The deployed amendments comprised granulated blast furnace slag (Merit?), cement kiln dust, fly ash, gypsum, sand, iron sulfide, and microsilica. The use of amendments was observed to improve the strength of cement-stabilized soft and wet sediments, where the use of granulated blast furnace slag (Merit) resulted in the greatest inprovement. Cement stabilization resulted in a reduced leaching of lead, whereas the leaching of copper and chromium from Hammerfest sediments increased substantially. In order to achieve the lowest total net transport of contaminants through the material, S/S recipes for environmental projects should not only be optimized with regard to physical strength, but also with regard to leaching and permeability.